1. Field of the Invention
The invention relates to the catalysis of urethane and epoxy resin reactions and particularly to the formation of such polymers in the form of cellular polyurethanes, polyurethane coatings, and epoxy bodies and films. The catalyst compositions comprise tertiary amine salts which decompose thermally to release the catalytically effective tertiary amine moiety.
2. Prior Art
In certain applications of polyurethanes and epoxy resins, it is desirable to prepare a composition comprising substantially all of the ingredients at a relatively low temperature and to bring about the rapid polymerization reaction at the time when the composition is heated to the activation temperature. When attempts are made to employ amines as the catalyst for such heat activatable compositions, difficulties are encountered because the amine tends to significantly promote polymerization at room temperature. Delayed reaction catalysis has previously been achieved by employing an acid salt of a tertiary amine. For example, a measure of delayed action catalysis has been achieved using materials such as the benzoate salt or the acetate salt of a tertiary amine. The propensity of such salts is to partly dissociate at room temperature as well as at elevated temperatures when introduced as catalyst in a polymer precursor system. Some dissociation occurs at room temperature, causing premature amine catalysis, thereby adversely shortening the useful "pot life" of the composition of ingredients. At elevated temperature reaction conditions, some of the amine has been unavailable for catalysis because of the reversibility of the dissociation phenomena.
In the balanced catalyzation of polyurethane compositions, it has been advantageous to use a mixture of amine catalyst and tin catalyst. However, the lack of compatibility between the benzoate salts of tertiary amines and tin catalysts has impaired growth of use of such catalyst compositions. Notwithstanding the continuing demand for polyurethane precursor compositions suitable for heat activated catalyzation, previous efforts to use the salts of tertiary amines as delayed action catalysts encountered troublesome disadvantages.